The eyes are a key point of infection for the novel coronavirus, a team of Hong Kong researchers said this week, detailing how the disease has higher rates of transmissibility through the eyes and airways when compared to H5N1, or the bird flu, and severe acute respiratory syndrome (SARS).
SARS-Cov-2, the virus that causes a COVID-19 infection, is nearly 100 times more effective at infecting the human conjunctiva -- a thin, clear tissue covering the eyeball and inner surface of the eyelids -- and upper respiratory airways than SARS, Dr. Michael Chan Chi-wai, who led the research team at Hong Kong University’s School of Public Health, told the South China Morning Post. The team's findings were published in the most recent issue of The Lancet Respiratory Medicine.
“We culture tissues from the human respiratory tract and eyes in the laboratory and applied them to study the SARS-Cov-2, comparing it with SARS and H5N1. We found that SARS-Cov-2 is much more efficient in infecting the human conjunctiva and the upper respiratory airways than SARS with virus level some 80 to 100 times higher,” Chan told the outlet. “This explains the higher transmissibility of COVID-19 than that of SARS. This study also highlights the fact that eyes may be an important route of SARS-CoV-2 human infection."
While SARS infected an estimated 8,000 people during the outbreak in the early 2000s, the number of confirmed COVID-19 cases to date approaches 4 million worldwide.
The news comes after Italy’s first coronavirus patient had detectable levels of virus genetic material in her eyes long after it cleared from her nose, according to a report published in the April 17 journal Annals of Internal Medicine. On the woman’s 27th day in the hospital, the virus’s genetic material was still detected through ocular swabs.
The Hong Kong team's findings highlight not only the importance of keeping your hands away from your face but also suggest a need for essential workers to wear protective eyewear, beyond just face masks and protective clothing, the South China Morning Post noted.
“Avoid touching your eyes, nose and mouth with unwashed hands,” the Centers for Disease Control and Prevention (CDC) advises in helping prevent a COVID-19 infection. The advice may prove more important than ever as warm spring weather brings seasonal allergies, stirring up itchy eyes.
Dr. William Schaffner, the medical director for the National Foundation for Infectious Diseases (NFID), previously shared several tips to avoid touching the face, including alarms and sticky notes as reminders, or even tying a ribbon around a finger.
Fox News's Madeline Farber contributed to this report.